Gear type fluid handling device



Nov. 12, 1963 w. s. MILLER 3,110,265-

GEAR TYPE FLUID HANDLING DEVICE Filed Aug. 3l, 1961 2 Sheets-Sheet l loV5 [15' *I4 V3 l 2o 4943 45 4 l2 4o 39 19 47 BY iL- TTOI2NEY Nov. 12,1963 w. s. MILLER 3,110,266

GEAR TYPE FLUID HANDLING DEVICE Filed Aug. 3l. 1961 2 Sheets-Sheet 2INVENTOR. wE/DELJ. 5. M/LLEQ ATTOQNEV United States Patent G 3,110,265GEAR TYlE FLUID HANDLING DEVICE Wendell S. Miller, 1341 Comstock Ave.,Los Angeles 24, Calif. Filed Aug. 31, 1%1, Ser. No. 135,229 9 Qlaiins.(Cl. 163-129) This invention relates to certain improvements in geartype iluid handling devices, such as gear pumps or fluid driven geartype motors or metering devices.

Devices embodying the -invention are of a general type including a pairof gears mounted in -a housing and meshing together in la manner suchthat iluid, usually liquid but in some instances a gas, flows past thegears and through the housing in accordance with the turning movement ofthe gears. When the device is to function as a gear motor, the iluid atthe inlet side of the device is maintained under pressure Iand acts todrive the gears. When the device is to function as a pump, on t-he otherhand, the gears are power driven, by an electric motor or the like, andact to pump fluid through the housing as they turn.

One disadvantage which has been inherent in prior gear type devices ofthis general character has been their inexibility of operation withrespect to the volume of iuid which is passed through the device foreach revolution of the gears. ri'his volume has been ydefinitely xed inprior gear type devices, with the result that where the device has beena motor, the output shaft has necessarily been driven at a certainpredetermined rate for a particular rate of huid tlow; and when thedevice has been a pump, the rate of fluid delivery has been definitelyiixed for a particular rate ci' rotation of the gears.

A major object of the present invention is to provide a gear arrangementin which the volume of lluid passed for each revolution of t1 gears isnot xed in this manner, but instead can be controllably varied, to`render :the device considerably more ilexible in operation than priorsimilar motors Iand pumps. Particularly contemplated is an arrangementin which the volume can be varied continuously through a rather wideoperating range, to allow for an intinite number of dierent rates offluid output in a pump, and an infinite number of diterent rates ofrotation of the output shaft in a gear motor.

To attain the desired change in volume of fluid passed, l employ vanassembly in which at least one of the two meshing gears of the device ismounted for axial shifting movement relative to the other gear. Thisvshifting movement then serves to vary the axial length or" the portionsof the gears which are in meshing engagement; and since only theportions of the gears which are in mesh at a particular time areeffective to pass fluid through the device, the volume of liuid ilowingpast the gears is changed. Thus, the desired iniinite variation involume of iluid handled is attained.

At the opposite ends of the gears, there are desirably provided specialend parts for confining the iiuid against gear oy-passing ow at thoselocations. These end parts may be mounted for shifting movement axiallywith the gears, and arc shaped in -a unique manner to engage the gearsand to engage one another in optimum tluid confning relation.

As one or both of the gears are shifted between difterent settings,there is a tendency in the present apparatus for a slight increase ordecrease in the overall volume or" iluid which is contained within thegear space in the housing of the device (between the end parts). Certainadditional `features have to do with arrangements acting to compensatefor this slight change of uid volume, and in one arrangement eiectingthis compensation in a manner also overcoming any resistance to shiftingof the gears by the uid.

3-,l lh Patented Nov. l2, 1963 The above and other features and `objectsof the present invention will be better understood from the followingdetailed description of the typical embodiments illustrated in theaccompanying drawings in which:

PEG. 1 is a section through a rst type of gear pump constructed inaccordance with the invention;

FlG. 2 is a plan View of the FIG. 1 device, shown partially in sectionon the line 2 2 of FIG. l;

FIGS. 3, 4 and 5 are transverse sections taken on lines 3 3, 4 4 and 55' respectively of FIG. l;

FIG. 6 is a perspective view of stripped pump of the FIG. 1 device,partly in section and showing the gears partially disengaged;

FiG. 7 is a fragmentary section taken on line 7 7 of FIGURE 6;

FIG. 8 is `a fragmentary section taken on line 8 S of HG. 1;

FG. 9 is a view similar to FIG. l, but showing a variational form ofdevice; and

FlG. l0 is `a plan view of the PIG. 94 unit.

The gear pump 1u shown in FIGS. 1 through 7 includes an outer housing11, typically formed of metal or other rigid material, and containingtwo meshing gears 12 and 13 acting to pump iluid through the housingbetween an inlet passage 14 and an outlet passage 15 (see PIG. 2). Thegears are driven by a motor 16, which may be a constant speed electricmotor, with the rate of lluid output of the pump being controlled byaxial movement of upper gear 12 along its rotary axis 17. This gear istypically actuated by means of la control lever represented at 1S.

Housing 11 contains an upper elongated cylindrical bore centered aboutaxis 17 and extending entirely through the housing from one of it-s endsZtl to the -other end 21. Beneath bore 19 (as viewed in FIG. 1), housing11 contains `a second cylindrical bore 21, typically of the samediameter as bore 1li, and centered iabout a second axis 22 which isparallel to and spaced from axis 17. Bore 21 preferably does not extendthrough the entire length of housing 11, but instead is closed atopposite ends by end walls 23 and 24 disposed transversely of axis 22.Gears 12 and 13 are mounted rotatably within bores 19 and 21respectively, for rotation about axes 17 and 22, with the majordiameters of the gears being substantially equal to the diameters of thebores (diameter D in FIG. 1). Thus, the gears are Very close tits withinbores 19 and 21, being only suiciently smaller lthan the bores to allowfor rotation of the gears about their individual axes. Axes 17 'and 22are spaced apart a -distance somewhat less than the diameter D of bores19 and 21, and in particular suiciently less than diameter D to allowfor full meshing of the teeth 25 4of the gears. Thus, the cylindersdened by the inner surfaces of bores 119 and Z1 intersect one 'anotherat the locations at which the two gears mesh together. In theillustrated arrangement, the teeth ZS of the gears are represented asextending directly axially along the outer surfaces of the gears.

Motor 16 rotatably drives a shaft 26 which is journaled for rotationabout axis 22 lby bearings 27 and 28. This shaft extends through endwall 29 of the housing, and entirely through gear 13, and `is rotatablykeyed to the gear to drive it and the meshing gear 12 in accordance withthe powered rotation of shaft 25. To the left or" gear 13, as viewed inFIG. l, this gear integrally or rigidly carries a short externmlycylindrical element 30, of a diameter corresponding to bore 21, to litclosely within that bore. In the simplest arrangement, this element 351is merely an externally cylindrical extension of the same piece of metalfrom which gear 13 is formed, with the gear teeth terminating in thetransverse plane represented at 31 in FIG. 1. rllhe outer end surface 32of element 39 is disposed transversely of axis 22, and annularly engages3 the previously ymentioned transverse end Iwall surface formed by thehousing.

At the opposite end or" gear 13, there is provided an elongated endelement 33, having a transverse end surface 34 engaging housing Isurface24. At 35, gear 13 and element 33 have annular surfaces abutting againstone another and disposed transversely of axis 22. Internally, element33l has a bore 36 through which shaft 26 extends in closely fittingrelation. Externally, element 33 has a cylindrical surface 37 which is aclose -lt within bore 21, and which is circularly continuous about axis22 except at the location of an upper recess 38 formed in element 33.

The upper gear 12 `may be essentially identical with lower gear 13,except that it does not have the extension 3d at the le-it end of thegear, but instead has a generally similar short externally cylindricalextension 39 formed at the righlt end of lgear 12 (as viewed in FIG. l).This extension 39 may :be integral with lgear 12, and of a diametercorresponding approximately to, but rotatable within, bore 19, with anG-ring of rubber or other sealing material received within a groove inextension 39 and engaging bore I? in lluid sealing relation. The uppergroove 38 formed in element 33 is a partial cylindrical groove, centeredarcuately about upper axis 17, and thereby forming in eiect acontinuation of upper bore 19, so that bore 19 and groove 33 formtogether a circularly continuous cylindrical bore engaged oy element 39and seal ring dil in fluid-tight relation. Beyond the end of element 33,at the location of housing wall 29, the bore 19 may be circularlycontinuous, even at the location of a bottom portion 41 thereof alignedwith groove 3S.

t its yleft end, gear 12 is rotatably connected to an elongate-d endpiece and shifting member 42, containing a bore adjacent the gear withinwhich a bea-ring 43 is received. Gear 12 may yhave an integral shaft dfiextending along axis 17, and journalled by bearing i3 to allow rotationof gear 12 relative to element 42. Bearing 43 is of a type acting as athrust `bearing to hold gear 12 in ixed axial position relative toelement 42, so that axial shifting ymovement ot element 12 serves tocorrespondingly shift gear 12 and its connected end part 3Q. Aboutbearing 43, elements 12 and d2 have transverse sur-faces in abuttingengagement at 45. As seen in FIG. 5, element 42 has a transversecross-section corresponding to that of the previously discussed endpiece 33. More particularly, element 42 has an external cylindricalsur-face 46 of a diameter corresponding substantially to that of bore19, and extending entirely about and along element 42 except at thelocation of a bottom arcuate groove 47 similar to groove 38 in part 33.Groove 47 is cylindrically or arcuately curved to form a continuation ofbottom bore 21, and to thereby closely engage the upper sur-faces ofelement Sil and gear 13 in dierent settings of the upper gear. T o dieleft ofY element 3l,-between the location of that element and endsurface Ztl of the housing, the crosssection of bore 19 is alteredslightly, to the extent or providing an arcuate partial cylindricalsurface 4S projecting upwardly into bore 19 and centered about `loweraxis 22. This surface 48 thus forms a leitward continuation of the upperportion of element 341, and mates with recess 47 formed in element 42. Aseal ring 49 may be received within a groove formed in housing 11 aboutpart 42, to peripherally engage part l2 and form a fluid seal betweenthat part and the housing.

Part 42 is actuated axially by means of Ilever 1S, which is pivoted atSil to a stationary support 51, and which has a slot S2 within which apin S3 projecting laterally from part 42 is received. As will beapparent, as lever 18 is swung to the iight as viewed in FIG. l, the pinand slot connections 52-53 correspondingly shifts element 42 and gear 12to the right within housing 11. In addition, this swinging movement oflever 18 displaces a part 54 to the right relative -to the housing, ybyvirtue of engagement of a nger S on lever 13 with part 54. The part Siintegrally carries two piston or plunger elements 56 and 57,

which elements are slidably received within coacting bores or cylindersS and 59 in housing 11 .for movement parallel to axes 17 and Z2. Part 54may be yieldingly urged to the lett by a coil spring represented at 6d,and the two plungers may be sealed with respect to their correspondingybores by O-.rings el. Bores 5S and 59 are placed in communication withinlet passage 14; and outlet passage 15 respectively by conduits d2 and63. The inlet and outlet passages 14 and 15 desirably have a lengthcorresponding to the axial length of the gears (see FIG. 2), and arelocated directly opposite the gears, in the full mesh PEG. l setting or"the gears.

To now describe the manner of operation of the device of FIGS. l through8, assume first of all that the apparatus is in the setting of FIG. l,and that motor 16 is electrically energized to continuously turn shaft26 and the two gears 12 and 13. Upper gear 12 turns in a clockwiseydirection as yviewed in FIG. 4, and -lowcr gear 13 turns in acounterclockwise direction. As the gears turn in these directions, theteeth 25 of the gears progressively pump fluid from right to left alongthe upper side of gear 12, and along the lower side of gear 13. The fullmeshing interengagement of the gears at the bottom or" gear 12 and thetop of gear 13 lprevents a reverse ilow of the lluid at that location.Thus, the device pumps fluid from inlet passage 14 to outlet passage 1Sat a rate dependent upon the rate of rotation of shaft 26.

If it is now desired to reduce the output of the pump, while maintainingthe same rate of rotation of the gears, lever 1S is shifted to the rightas viewed in FIG. 1, as to the position represented in FIG. 6, so that aright hand portion of upper gear 12 is moved out of engagement withlower gear 13, and moves into arcuate recess 33 formed in .part 33.Similarly, a left hand portion of gear 13 is now received within aportion of bottom groove 47 formed in element 42. In this condition, theonly effective pumping portions of the gears are those portions whichremain in mesh with one another. The portion of each gear which is notin mesh with the other gear, for example the portion of gear 13 shown inFIG. 7, acts merely to pump iluid around in a circle, with the sameamount of iiuid being pumped from outlet 1S to inlet 14 as is pumped inthe opposite direction from inlet 14 to outlet 15. Element 42 may beshifted continuously through an infinite number of positions from theFIG. l maximum flow setting to a zero flow setting just beyond that ofFIG. 6 `and in which no portions of the two gears are in mesh.

As upper gear 12 of FIG. l is shifted to the right, and the gears movepartially out of mesh, the total volume of luid which can be containedwithin the housing at the locations of the gears, between end parts 30and 33, and between end parts 39 and 42, increases progressively as aresult of the movement of the gears out of mesh. To compensate for thiseffect, pistons 56 and 57 pump small charges of iiuid into the inlet andoutlet sides of the device in accordance with such rightward movement ofgear 12. The plungers or pistons 56 and 57, and their bores 58 and 59,are so dimensioned as to exactly compensate for the effect discussed,and thereby avoid any overall pumping of uid into or out of the device10, solely in response to axial `shifting movement of gear 12 and itsassociated parts. This compensation is especially desirable where theduid being handled is a liquid and is therefore incompressible.

I'f it is desired to utilize the unit 1G of FIGS. 1 through 8 as a fluidactuated motor, rather than as a gear pump, then fluid under pressure issupplied to inlet passage 14, and acts to drive gears 12 and 13 in thedirections illustrated in FIG. 4. The unit represented at 16- in FIG. 1may then be considered as a device to be driven by the fluid actuatedgear motor 10. The rotation of the gears drives shaft 25, which in turndrives the actuated unit 16.

FIGS. 9 and 10 show another form of the invention, which is very similarto that of FIGS. l through 8 except in the respects speciiicallydiscussed below. Housing alleges lia of the FIGS. 9 and l0 devicecontains two cylindrical bores 17a and "tt/z, within which `gears 12aand 13a? are slidably received. Gear 12a has at its right end anexternally cylindrical extension 39a corresponding to that shown at 39in FlG. l, except that extension 39o is longer axially than part 39, andcontains a splined bore 6d within which a splined end 65 of motor drivenshaft 26a is received. Shaft 25a extends through a bushing 27a carriedby the housing, in fluid sealing relation, so that a closed endcompartment 66 is formed within the housing axially beyond the portion39a of the upper gear assembly. As will be apparent, the splinedconnection oil-65 allows motor la to continuously drive element 39a andthe connected gear i251, while at the same time permitting axialmovement of parts 12a and 39a.

As in the case of the upper gear, the cylindrical extension 36a of lowergear 13a is considerably longer in PEG. 9 than was the correspondingpart 3@ in FIG. l, and forms an end compartment 67 within the endportion of the housing. A shaft or rod 63 projects from element 3ft-Lzthrough a sealing bushing 69, and has rack teeth 75 formed on its uppersurface for engagement with a pinion 71, to actuate elements 13a andSila axially within the housing. A hand operated wheel 72 may beconnected to pinion 7l, for turning it.

At the left end of upper gear 12a there is provided a part 42a, whichmay be considered to be essentially identical with part 42 of FIG. l,the gear being connected thereto `by bearing 43a so that parts 12o andi252 move axially together, with gear lZa being rotatable relative topart 42a. Connected to part 42a, there is a rod or shaft 73, whichprojects through a sealing bushing 74 within an end wall 75 of thehousing, and has rack teeth 76 at its underside `for engagement withpinion 7l.

To the right of gear 13o, there is provided a part 33a which may beessentially the same as part 33 of PEG. l, except that part 33a isaxially movable with parts 13a and 39a, and in order to allow for suchmovement of part 33a, elements 13a. and 33a are connected together by athrust bearing S7 of the same type provided at 43a. Part 33a has anupper partial cylindrical groove Sa within which elements 12a and 39aare receivable, and part 42a has a similar downwardly facing partialcylindrical groove 47a within which parts i311 and 3tlg. are receivable.It is noted that end wall 75 of the housing is oset sutiiciently far tothe right of end wall 77 to allow part Sila in all settings to projectbeyond the inner surface 78 of end wall 75, and thus isolate chamber 67from a chamber 79 provided between end wall 75 and element 42a.Similarly, at the opposite end of the device, part 39a projects in allsettings beyond transverse surface S9 of end wall Sl, to form a chamberor compartment S2 at the right end of element 33a, which chamber is inall conditions isolated from compartment 66, The two compartments 67 andSi) at opposite ends of the lower gear assembly are both placed incommunication with inlet passage 14a (and therefore with one another) byconduits 83 and Sii; and similarly the two compartments 66 and 79* atopposite ends of the upper gear assembly are placed in communicationwith discharge passage 15a (and with one another) through conduits 85and 86.

in describing the operation yof the device of FIGS. 9 and l0, assumethat motor loa is turning at a uniform rate of speed, and that gems 12aand 13a are initially in their yfully meshed positions of FiG. 9. Inthis condition, the gears act in the same manner previously discussed inconnection with the first form of the invention to pump fluid from inletpassage ida to discharge passage l'n. It it is desired to reduce therate of output, while still maintaining the same rate of rotation of thegears, handle 72 and its connected pinion 7l are turned in a ydirectionto move upper gear 12a and its connected parts Sa and 42:1 to the right,while simultaneously moving roller gear 13a and its connected parts 39aand 33o to the lett a corresponding distance. Thus, portions of thegears move out of mesh, and the effective axial lengths of the gears forpumping purposes therefore decrease, with resultant correspondingreduction in the pumping rate.. The intercommunication provided betweenchambers 67 and Stir, and the inlet passage la, through conduits 33 and8d, allows fluid from chamber 67 to ow into chamber 32 upon leftwardmovement of the lower gear assembly, and also compensates for the slightincrease in tiuid receiving volume Iat the location of gear lrz, whichslight change in volume was oompensated for piston 57 in FG. l.Similarly, the intercommunication between chambers 66 and 79, and`discharge passage 15a, allows fluid `flow between these chambers, andcompensates for the slight change in volume at the `discharge side ofthe unit.

l claim:

l. A gear type fluid handling device comprising a housing, and two gearsin said ,housing having teeth meshing at a predetermined location andconstructed to pass fluid from an inlet side of the gears to a dischargeside thereof in accordance with the rate of rotation of the gears, bothof said gears being shiftable axially in the housing and relative to oneanother and being operable `by such shifting movement to vary theeifective volume of tluid which ilows past the gears from said inletside to said discharge side upon each revolution `of `the gears, saidgears being shiftable to a partially meshed position in which iirstportions of the gears are in axially overlapping meshing relation, butin which an end portion of each `gear projects Vaxially beyond the othergear, out of mesh therewith, and has the entire space between its teethfilled with uid.

2. A gear type fluid handling device as recited in claim l, includingcontrol means loperable to simultaneously shift said `two gears inopposite axial directions.

3. A gear type :ilu-id handling device comprising la housing, two gearsin said housing having teeth meshing at a predetermined location andconstructed to pass iluid from an inlet side of the gears to a dischargeside thereof in accordance with the rate of rotation of the gears, bothof said gears being shiftable axially within the housing and relative toone another and being operable by such shifting movement to vary theeective volume of fluid which tiows past the gears from said inlet sideto said `discharge sid-e upon each revolution of the gears, two pairs ofend parts `associated with said two gears respectively, the two endparts of each of said pairs being received at opposite ends of theassociated gear and being movable axially therewith, said housingforming two end compartments Aat opposite ends of a iirst of said gearsand axially beyond the two end parts associated therewith, said housingforming two additional end compartments at opposite ends of the secondgear and axially beyond .the two end parts associated therewith andisolated from said first mentioned `end compartments, means placing saidfirst mentioned end compartments in communication with one -another andwith one of said linlet and Idischarge sides of the gears, and meansplacing said additional end compartiments in communication with oneanother and with the other of said sides ofthe gears.

4. A gear type uid handling device as recited in claim 3, in which saidhousing contains two parallel bores containing said gears respectivelyand their end parts and forming said end compartments at opposite endsot the bores, one of said ibores projecting beyond the other at one end,and said `other bore projecting beyond said one bore at the second endof the bores.

5. A gear type fluid handling device comprising a housing, two gears insaid housing having teeth meshing at a predetermined location andconstructed to pass fluid from an inlet side of the gears to a dischargeside thereof in accordance with the rate of rotation of the gears, atleast lone of said gears being shiftable axially in the housing andrelative to the other gear and being operable by such shifting movementto vary the eective volume `of fluid which ilows past the gears fromsaid inlet side to said discharge side upon each revolution of thegears, compensating means for feeding small amounts of iiuid to both ofIsaid inlet and discharge sides ot the gears -in response to relativeaxial shifting move-ment of said gears to compensate for the change iniluid capacity at said sides resulting from said shifting movement, andmeans for conducting fluid from said compensating means to both of saidinlet and discharge sides of the gears.

6. A gear type fluid handling device comprising a housing, two gears insaid housing having teeth meshing at a predetermined location andconstructed to pass fluid from yan inlet side of the gears to adischarge side thereof in accordance With `the rate of rotation of thegears, at least one of said gears being shiftable axially in the housingand relative to the other gear and being operable by such shiftingmovement to vary the effective volume of iluid which iiows past thegears from said inlet side to said discharge side upon each revolutionof the gears, two cornpensating pumping units for pumping small amountsof uid to both of said inlet and discharge side-s of the gears inresponse to relative axial shifting movement of said gears in quantitiesto compensate for the change in iluid capacities at said sides resultingfrom said shifting movement, means for conducting duid from said pumpingunits respectively to said inlet and discharge sides of the gears, andmeans for actuating said pumping units in correspondence with therelative shifting movement of said gears.

7. A gear type fluid handling `device comprising a housnig, two gears insaid housing having teeth meshing at a predetermined location andconstructed to pass luid from an inlet side ot the gears to a dischargeside thereof in accordance with the rate of rotation of the gears, atleast one of said gears being shiftable axially in the housing andrelative to the other gear and being operable by such shifting movementto vary the effective volume of iiuid which ows pass the gears from saidinlet side to said discharge side upon each revolution of the gears, twocompensating piston and cylinder pumping units for pumping small amountsof duid to both or" said inlet and discharge sides of the gears inresponse to relative axial shifting movement of said gears in quantitiesto compensate .for the change in fluid capacities at said sidesresulting from said shifting movement, means for conducting uid lfromsaid piston and cylinder pumping units respectively to said inlet anddischarge sides of the gears,

and Ameans for actuating said piston and cylinder pumping units incorrespondence with the relative shifting movement of said gears.

8. -A gear type uid handling device comprising a housing, two gears insaid housing having teeth meshing at a predetermined location andconstructed to pass iiuid from an inlet side of the gears to a dischargeside lthereof in accordance with the rate of rotation of the gears, atleast one of said gears being shitable axially in the housing andrelative to the other gear and being operable yby such shifting movementto vary the etfective volume of lluid which flows past the gears fromsaid inlet side to said discharge side upon each revolution of thegears, two compensating pumping units for pumping small amounts of duidto -both of said inlet and discharge sides of the gears in response torelative axial shifting movement of said gears in quantities tocompensate for the change in fluid capacities at said sides resultingfrom said shifting movement, means for conducting iiuid trom saidpumping units respectively to said inlet and discharge sides of thegears, actuating mechanism for relatively axially shifting said gears,and mechanism operated by said actuating mechanism for ope-rating saidpiston and cylinder pumping units in correspondence with the relativeshifting movement of said gears.

9. A gear type lluid handling device comprising a housing, 'two gears insaid housing having teeth meshing at a predetermined location andconstructed to pass fluid from an inlet side of the gears -to adischarge -side thereof in accordance with the rate of rotation of thegears, both of said gears being shitable axially in the housing andrelative to one another and being operable by such shifting movement tovary the eective volume of uid which ilows past the gears from saidinlet side to said discharge side upon each revolution of the gears, andcompensating means for feeding small amounts of fluid to both of saidinlet and discharge sides of the gears in response to relative axialshifting movement of said gears to compensate for lthe change in uidcapacity at said sides resulting from said shifting movement, saidcompensating means including means forming a iirst pair of endcompartments at opposite ends of one of said gears and varying in sizeupon axial movement of the gears, mean-s forming a second pair of endcompartments at opposite ends of the other gear and varying in size asthe gears shift and isolated from communication with said rst pair ofcompartments, means connecting said rst pair of said lcompartments tothe inlet side of said gears, and means connecting the second pair ofcompartments to the discharge side of said gears.

References Cited in the tile o this patent UNITED STATES PATENTS 543,872Kendall Aug. 6, 1895 549,854 Norman Nov. 12, 1895 711,662 Herdman Oct.21, 1902 788,848 Riegel May 2, 1905 1,223,734 Rinehart Apr. 24, 19172,652,419 Moore et al. Aug. 25, 1936 2,293,126 Fersing Aug. 18, 19422,368,789 Tucker Feb. 6, 1945 2,570,411 Vickers Oct. 9, 1951 2,684,636Heldenbrand July 27, 1954 2,804,016 Moore Aug. 27, 1957 2,955,541 MooreOct. 11, 1960

1. A GEAR TYPE FLUID HANDLING DEVICE COMPRISING A HOUSING, AND TWO GEARSIN SAID HOUSING HAVING TEETH MESHING AT A PREDETERMINED LOCATION ANDCONSTRUCTED TO PASS FLUID FROM AN INLET SIDE OF THE GEARS TO A DISCHARGESIDE THEREOF IN ACCORDANCE WITH THE RATE OF ROTATION OF THE GEARS, BOTHOF SAID GEARS BEING SHIFTABLE AXIALLY IN THE HOUSING AND RELATIVE TO ONEANOTHER AND BEING OPERABLE BY SUCH SHIFTING MOVEMENT TO VARY THEEFFECTIVE VOLUME OF FLUID WHICH FLOWS PAST THE GEARS FROM SAID INLETSIDE TO SAID DISCHARGE SIDE UPON EACH REVOLUTION OF THE GEARS, SAIDGEARS BEING SHIFTABLE TO A PARTIALLY MESHED POSITION IN WHICH FIRSTPORTIONS OF THE GEARS ARE IN AXIALLY OVERLAPPING MESHING RELATION, BUTIN WHICH AN END PORTION OF EACH GEAR PROJECTS AXIALLY BEYOND THE OTHERGEAR, OUT OF MESH THEREWITH, AND HAS THE ENTIRE SPACE BETWEEN ITS TEETHFILLED WITH FLUID.